This invention has particular application to glow plugs used in internal combustion engines of model airplanes of the radio controlled type. In such engines, reliability is of great importance. The abilities to idle or run at low speed and then quickly to accelerate smoothly, without faltering or hesitating (staggering), to high speed and smoothly to decelerate from high speed to low, are all essential.
The conditions of operation and the performance requirements of the glow plugs of radio controlled model airplane engines are different from those involved in engines used for racing. Furthermore, it is desirable in glow plugs used in radio controlled aircraft engines to have a much longer effective life than that of racing plugs, which, as explained in the application of which this is a continuation-in-part, are commonly used for one flight or at the most two or three.
One of the objects of this invention is to provide a glow plug for radio controlled model aircraft which minimizes or eliminates stagger, and provides either a faster top speed or better fuel efficiency at the same speed than such plugs known heretofore.
Another object is to provide such a plug which is durable and dependable.
Still another object is to provide a high quality plug which is easy to manufacture.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.